Vocabulary Size: How to Measure What You Actually Have

"I know 8000 words" doesn't tell you anything until you separate passive from active vocabulary. Here are three free tests, what each measures, the realistic gap between recognising and using words, and how much vocabulary each major exam actually wants.

1. Why "I know X words" is meaningless

If you ask someone how many words they know and they say 8000, that number conflates two very different things:

  • Passive vocabulary — what you recognise when reading or listening
  • Active vocabulary — what you can produce when writing or speaking

Active typically runs at ~40% of passive. So "8000 words" usually means about 3200 truly usable.

2. Approximate vocab-size by CEFR level

CEFRPassiveActive
A1600–800250–350
A21200–1600500–700
B12500–30001200–1500
B25000–60002500–3000
C18000–100004500–5500
C212000+7000+

Numbers are mid-range estimates from corpus research; specific tests may diverge.

3. Three free tests you can take today

Test 1 — testyourvocab.com

About 10 minutes, you check off words you recognise. Returns a passive vocabulary estimate. Best for first-time baseline.

Typical results:

  • Native speaker (adult): ~28,000
  • B2 non-native: ~6,000
  • C1 non-native: ~8,000

Test 2 — Lexile reading assessment

Reads a passage, asks comprehension questions, outputs a Lexile score (700L–1300L+) mapped to your reading level. Best for "what difficulty of material can I actually understand?"

Approximate CEFR map:

  • 700–900L ≈ B1
  • 1000–1100L ≈ B2
  • 1200–1300L ≈ C1

Test 3 — TTR (Type-Token Ratio) on your own writing

Open our writing tool, write a 250-word Task 2 essay, and check the TTR statistic:

TTRDiagnosis
< 45%Vocabulary repetition; active range tight
45–55%Normal B2
55–65%C1 territory
> 65%Near-native / C2

This is the simplest way to check whether your active vocabulary is sufficient.

4. Vocabulary requirements per exam (rough thresholds)

Exam + targetPassiveActive
IELTS 6.0~5000~2500
IELTS 6.5~5500~2800
IELTS 7.0~7000~3500
PTE 65~6000~3000
LanguageCert B2~5500~2800
LanguageCert C1~8500~4500
Password 6.0~5500~2800
DET 120~5500~2800
DET 140~7000~3500

Note: target 6.5 on most tests corresponds to about 5500 passive — which is exactly what our L2 vocabulary list is built around.

5. Three stages of vocabulary growth

Stage 1 — Foundation (A2 → B1)

Stage 2 — Expansion (B1 → B2)

  • Focus: academic + journalistic words 2000–5000
  • Method: word + collocation + context
  • Tools: L2 vocabulary + BBC Learning English reading

Stage 3 — Refinement (B2 → C1)

  • Focus: precise collocations + synonym distinctions, 5000–8500
  • Method: word + 2–3 collocations + one negative example
  • Tools: L3 vocabulary + Economist + writing self-rubric

6. Why "wordlist cramming" is inefficient

Imagine cramming 50 new words a day. After a month:

  • True retention: ~60% = 900
  • Usable in writing: ~30% = 450
  • Usable in speaking: ~15% = 225

Now imagine 50 new collocations a day. After a month:

  • True retention: ~80% = 1200
  • Writing-usable: ~60% = 900
  • Speaking-usable: ~40% = 600

Two to three times as effective. Treat collocations as the unit of vocabulary growth, not single words.

7. Action steps this week

  1. Take testyourvocab.com — baseline passive
  2. Write a 250-word essay; check TTR — current active
  3. Use the table in §4 to identify how far you are from your target
  4. Choose L1, L2 or L3 vocabulary to match
  5. Re-test TTR weekly to watch active vocabulary rise

Vocabulary is not about quantity — it's about active-passive balance. A new usable collocation is worth ten new words you only recognise.